But now, The Script frontman Danny, 31 - who once described Bo as 'absolutely everything' - has had a change of heart and has been begging Irma to give their relationship another go.
And Irma, a Lithuanian-born model, has agreed – as long as he abides to a set of rules, which includes staying away from Bo.
Irma was frustrated with Danny's closeness to Bo, who won the BBC show, so in order to make a go of their relationship for a second time, she has slapped a 'Bo ban' on her man – and he's agreed to it.
Danny and Bo, 27, refused to deny rumours that they were dating for months, and the break-up of his relationship to Irma only fuelled further speculation of a romance.
But last month, Danny spoke out for the first time, insisting that he hadn't dated Bo and claiming he didn't deny the rumours because it was "good for publicity."
He said: "We decided to let the story run to keep her name in the papers so that she was still in the public sphere when she released a single."
It seems Danny has had time to reflect on his separation from Irma, who he dated for four years, and calls their split 'heartbreaking'.
Read the full story in this week's Reveal magazine.
What do you think about Danny and Irma giving their relationship another go? Let us know below.
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